prusa3d.com auto tramming

My take on rack&pinion for folding autotramming microswitch up and down for the prusa3d.com i3. Screws right onto the extruder and fan. Based on Martin Rice's idea for the Wilson II. http://community.reprapwilson3d.com/t/a-new-way-to-probe-the-print-bed-bed-leveling/66
Uses the rack and pinion library by sasa - http://www.thingiverse.com/thing:172508

In action: https://www.youtube.com/watch?v=32_TJb0Dwr4